Boom for low bucks

Hi,

You guys will probably laugh but I'm gonna try this anyway.

I am in the process of trying to put a decent sounding system together for low $$ for my son.  Here is where I'm at:

Spent $6.50 on Ebay for an old Jensen A220 amp that works fine.  It is 120Wx2@4ohm or 250rms bridged.  Since it is old there is no LPF.  My main question is does anyone know where I can get a couple of 3 milliHenry coils for a 1st order or a 9mH coil for a 2nd order LPF and also if I can find these coils should I install them before or after the amp if I have a choice?  Radio Shack did not have them.

I have an old home Panasonic system with a set of "Thrusters" that have a 10" sub and a 10" passive radiator.  The speakers are rated at only 40W and are already about gone after 25+ years.  I bought a new Infiniti 1040 sub.  I plan to try and use the existing passive radiator and try to add some weight to dampen it to match the 1040 if possible.  The 1040 calls for a ported enclosure of 1.75 cubic feet.  The Thruster cabinet is well made and is 1.8.  I think the 10" passive radiator is equal to the 3"dia x 9L port requirement for the 1040??? Please correct me if I'm wrong.

Of course my son thinks I'm nuts for going to all this trouble and would like to just go and buy a new amp but he doesn't have a job yet!  I am able to do this but like to "tinker" and see if I can come up with a cheap box that sounds as good as his buddies who have spend several hundred $$ on their systems that sound mediocre to me at best.

Ok, you can stop laughing now :D

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Going deaf, need more SPL...

Not laughing, there's nothing wrong with trying to make a system work with older or cheaper gear, as long as you know that's what you're doing.  I laugh at people with flea-market gear who think it will sound like the top of the line.

In any case, for passive crossover parts, the cheapest and most readily available are from Parts Express or Madisound.  Now as far as trying to fit the Infinity speaker into the Panasonic enclosure, go for it and see what it sounds like.  You might be surprised.  But I bet you will be disapointed.  I'd suggest making a simple MDF enclosure for the Intinify woofer.  As I recall a Reference 1040 works best in a small (0.5 to 0.75 cuft) sealed enclosure.  Screw and glue together a 12"X12"X10" cube out of 3/4" MDF, seal it with silicone, add your woofer and see how it sounds.  The MDF will cost you less than $15.

Cheers!

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well, I took an old sony amp (two channel) and some $20 walmart 6.5" speakers with some tweeters and hooked it up in the back of my car. I took it to the beach and threw the speakers out and cranked them up for tunes on the beach. worked beautifully. cost me $20.

if you can get that radiator tuned correctly it will work great, but if not, you are better off to go with a new box. not too hard to build.

-Drew

Wait, is tis a home or car stereo system? By the reference to the panasonic home speakers I have to assume it's for a home.

If that is indeed the case, I recommend that you purchase a pair of Cerwin Vega D-3. They cost ~$100 a pair. I can guarantee you that you won't be disappointed(I own a pair)

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I agree with DYohn about building a new enclosure with 3/4" MDF.  Those Thruster cabinets are not nearly HD enough for subwoofer use.  If you're still looking at gear, I just saw a sweet deal on a USacoustics 2 channel amp that I would just love to have reason to buy:

https://www.thezeb.com/p-USacoustics-USX-2050-2-Channel-Amplifier-105480.htm

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Dyohn, can i quote you on that in my signature?

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don't rush into things...you'll get ripped off

sorry dont know how to use the quoting system.

"I laugh at people with flea-market gear who think it will sound like the top of the line."

lol

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don't rush into things...you'll get ripped off

Deusqe, reading that sentence out-of-context sounds very un-DYohn-like.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Poormanq45 wrote:

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Wait, is tis a home or car stereo system? By the reference to the panasonic home speakers I have to assume it's for a home.

If that is indeed the case, I recommend that you purchase a pair of Cerwin Vega D-3. They cost ~$100 a pair. I can guarantee you that you won't be disappointed(I own a pair)

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Sorry, I should have been more specific.  I am using my old Panasonic box that is pretty heavy duty to build the sub for my son's '02 Mustang. 

I know it won't be competition quality but I am trying to teach my son that sometimes it is rewarding to build something out of nothing rather than just go out and buy it.  Especially at his age (16) with only odd jobs so far and over $200/month for insurance that he must pay.  I could go out and buy him a system but that would be too easy!  Man I'm starting to sound like my dad

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Going deaf, need more SPL...

stevdart wrote:

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I agree with DYohn about building a new enclosure with 3/4" MDF.  Those Thruster cabinets are not nearly HD enough for subwoofer use.  If you're still looking at gear, I just saw a sweet deal on a USacoustics 2 channel amp that I would just love to have reason to buy:

https://www.thezeb.com/p-USacoustics-USX-2050-2-Channel-Amplifier-105480.htm

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Thanks stevdart, that looks like a great deal.  I think with the setup I am putting together 150 to 250W RMS is going to be just fine.  Might not rattle windows in nearby buildings but inside the Mustang it should sound great. 

If the Thruster cabinets don't hold up or resonate I bought plans from Decware to build a Deathbox II for the Infinity 1040.  Any comments good or bad on the Deathbox from anyone?

Thanks

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Going deaf, need more SPL...

Here's what it says in the Infinity manual:  "Bandpass enclosures often provide the most output available from any amplifier and subwoofer combination at the expense of sonic accuracy."  With that in mind, a bandpass enclosure is one of the most difficult to build...and get a reasonably good-sounding subwoofer.  If you are providing 200 to 250 watts at the 4 ohm impedance load that sub will provide, a small sealed box would be the best route for sound quality and mostly effortless construction.  With almost any subwoofer that calls for a 1 or 1.25 cu. ft. volume, you can easily go higher without harm...and usually get better low end response too.

Those cabinets for the Thrusters are most likely 5/8" MDF, so you could use those with a second layer of MDF or plywood.  I would probably use 1/4" exterior grade plywood to beef them up, using glue and screws across the whole contact area.  You can sometimes find it in 4 X 4 sheets, which will save you some construction costs.  And you can screw a square of 5/8" MDF (old shelving or pre assembled cabinetry lying around the basement should provide this) over the passive radiator hole on the inside....and no one will be the wiser.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

stevdart wrote:

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Those cabinets for the Thrusters are most likely 5/8" MDF, so you could use those with a second layer of MDF or plywood. I would probably use 1/4" exterior grade plywood to beef them up, using glue and screws across the whole contact area. You can sometimes find it in 4 X 4 sheets, which will save you some construction costs. And you can screw a square of 5/8" MDF (old shelving or pre assembled cabinetry lying around the basement should provide this) over the passive radiator hole on the inside....and no one will be the wiser.

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I just built a 3.5ft^3 ported box out of 5/8MDF. I found that you can make it EXTREMELY strong by mounting a 1x2 vertically on the panels that over 1.5ft long. When I say vertically I don't mean top to bottom, I mean the 1x2 is run the length of the panel to be reinforced and screwed directly to it. Also, corner bracing works great too. With those two combined I am able to jump up and down on the enclosure(I'm 180lbs) in the middle of the longest panel, 28inx18in, and it does NOT flex at all.

So, I say if you can, use the panasonic box.

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Now I know why you guys call it Fleabay...

I bought my Infinity from a seller claiming it was "Brand New 2005" and when it arrived it had been damaged.  The outer rim was bent probably a quarter inch.  Saved almost $10 though whoopee!!!

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Going deaf, need more SPL...

ouch. Was that damage in the description? If not you can take it up with Ebay

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